SAN SALVADOR — A fisherman who says he drifted at sea for more than a year, surviving on raw fish, turtles, and birds, is in stunningly good health but psychologically fragile, medical experts said Wednesday as the man recuperated in a hospital in his native El Salvador.

Jose Salvador Alvarenga underwent a battery of tests after returning home from the Marshall Islands, where he showed up after what he has described as 6,500-mile journey from Mexico across the Pacific that began when his small fishing boat was thrown off course by bad weather.

The medical team that examined him at the San Rafael hospital in the Salvadoran capital said he was in remarkably good physical health: with no skin lesions from overexposure to the sun, and no cardiovascular or kidney issues. His only physical problem, doctors, was a case of anemia.

‘‘All of the exams have been basically close to normal. It’s incredible,’’ said El Salvador’s minister of public health, Maria Isabel Rodriguez.

She and other Salvadoran experts who looked at Alvarenga’s results said they had no doubt about the veracity of his tale, so incredible that it left many skeptical even in the absence of an alternate explanation for his appearance on the Pacific Island atoll.

‘‘He challenges ideas about human physiology that we’ve had for a long time, but miracles exist and I don’t think there’s any reason to doubt him,’’ hospital director Yeerles Ramirez told reporters.

All of the doctors expressed concern about Alvarenga’s mental state, however, saying he appeared shaken and asked to be given as much privacy as possible.

‘‘He’s been telling us, ‘Let me rest.’ That’s his phrasing, that we let him rest, and that people aren’t taking pictures of him,’’ Rodriguez said.

She said that after Alvarenga arrived at the San Salvador airport late Tuesday and saw dozens of waiting reporters, photographers, and cameramen, ‘‘he quickly fell into a depression and started crying because he’s not ready to talk to the whole world.’’

Alvarenga, 37, has asked for tortillas and a pupusa, a thick stuffed corn tortilla that is a Salvadoran specialty, and he has already eaten a tortilla with cheese, Rodriguez said.

She said Alvarenga told doctors that he had given up hope of being rescued after several large ships came near his small fishing boat, with sailors on at least one even greeting him, but none tried to rescue him.

‘‘They passed close by, he asked them for help, and they didn’t want to give it,’’ she said.

Alvarenga will remain hospitalized for at least two days while he rests and undergoes a series of exams, among them a test of his kidney function, Ramirez told reporters outside the hospital.